Humanitas Research Hospital and Fondazione IRCCS Policlinico San Matteo are the two Italian centers that took part in the literature review of total marrow irradiation (TMI), an innovative radiotherapy technique used in the preparatory stages (the so-called conditioning) of patients with leukemia undergoing bone marrow transplantation.

The review, titled Total marrow and total lymphoid irradiation in bone marrow transplantation for acute leukaemia, was published in early October in The Lancet Oncology, one of the most prestigious Clinical Oncology journals. It was written by a team of international researchers, including Pr. Marta Scorsetti, Head of Radiotherapy and Radiosurgery of Humanitas and professor of Humanitas University, Pietro Mancosu, physicist of Humanitas and Pr. Andrea Filippi, Director of Radiotherapy at the San Matteo Polyclinic in Pavia.

The value of radiotherapy before bone marrow transplantation

As explained by Pr. Armando Santoro, Director of Humanitas Cancer Center, radiotherapy has been used in the conditioning of patients – candidates for bone marrow transplantation already in the original study of Pr. Donnall Thomas, who was awarded Nobel Prize for Medicine in 1990 precisely for his discoveries concerning the transplantation of bone marrow in hematological diseases.

In blood conditions such as leukemia, lymphoma and myeloma, radiation is used to suppress the recipient’s immune system to prevent rejection of the donor marrow and to eliminate cancer cells that remain after chemotherapy treatments.

A new radiotherapy technique to spare healthy tissue

“Historically, these patients received Total Body Irradiation (TBI). By definition, in this approach, the whole body is irradiated: both the bone marrow and the surrounding organs, causing possible toxicity to healthy tissues. Precisely for this reason, Jeffrey Wong, professor and director of the radiotherapy department of City of Hope and first author of the study, proposed in 2005 total marrow irradiation, a radiotherapy technique able to target the marrow but spare the surrounding organs at risk,” added Pr. Marta Scorsetti, co-author of the study.

Total Marrow Irradiation at Humanitas

Thanks to the efforts of the Humanitas radiotherapy team, the first patient has been treated with total marrow irradiation with linear accelerator and volumetric technique in 2010. It was one of the first cases in the world.

As the physicist Pietro Mancosu, one of the authors of the paper, points out: “Total marrow irradiation was made possible thanks to the ability to make the most of the technological advancement in radiotherapy treatment systems and the processing power of modern computers.

It is, in fact, the most complex treatment in the radiotherapy field. The volume to be irradiated is much larger than the volumes that are usually treated in radiotherapy (over 10,000 cm3 compared to an average of 1-1,000 cm3). For this reason, the treatment lasts about an hour, much longer than other linear accelerator sessions, which normally require only 15 minutes. The implementation of this technique was possible thanks to the collaboration among hematologists, radio oncologists, medical physicists, and radiology technicians.”

Pr. Andrea Filippi, extraordinary professor of Diagnostic imaging and radiotherapy at the University of Pavia and director of the Oncological Radiotherapy Department of the IRCCS Policlinico San Matteo Foundation in Pavia and the corresponding author of the paper, stresses that “at the moment, only very few centers around the world have introduced this technique into clinical practice.”

“In the paper – continues Filippi – we propose several ways of accelerating the development of this technique for its implementation in multiple centers, with the aim of increasing our ability to control these conditions and reduce toxicity in the short and long term”.